The superhero's alter ego, Robert Downey Jr., found that out first-hand this week, when he encountered 1½-year-old super-fan Jaxson Denno – who just couldn't wait to meet Iron Man.
Only problem: Downey, in the Western Massachusetts towns of Sunderland and Shelburne Falls to shoot his latest, The Judge, was not wearing his Iron Man outfit.
That did not please Jaxson, as this photo shows.
Not to worry, though – Downey, 48, soon brought a smile to the boy's face.
"He was fine as soon as he talked to him," Jaxson's mother, Heather Denno, told PEOPLE, explaining that her young son "was so confused because I kept telling him it was Iron Man and he knew it wasn't. Well, not Iron Man in the suit."